Bioavailable iron titrations reveal oceanic Synechococcus ecotypes optimized for different iron availabilities.

The trace metal iron (Fe) controls the diversity and activity of phytoplankton across the surface oceans, a paradigm established through decades of in situ and mesocosm experimental studies. Despite widespread Fe-limitation within high-nutrient, low chlorophyll (HNLC) waters, significant contributions of the cyanobacterium Synechococcus to the phytoplankton stock can be found. Correlations among differing strains of Synechococcus across different Fe-regimes have suggested the existence of Fe-adapted ecotypes. However, experimental evidence of high- versus low-Fe adapted strains of Synechococcus is lacking, and so we investigated the transcriptional responses of microbial communities inhabiting the HNLC, sub-Antarctic region of the Southern Ocean during the Spring of 2018. Analysis of metatranscriptomes generated from on-deck incubation experiments reflecting a gradient of Fe-availabilities reveal transcriptomic signatures indicative of co-occurring Synechococcus ecotypes adapted to differing Fe-regimes. Functional analyses comparing low-Fe and high-Fe conditions point to various Fe-acquisition mechanisms that may allow persistence of low-Fe adapted Synechococcus under Fe-limitation. Comparison of in situ surface conditions to the Fe-titrations indicate ecological relevance of these mechanisms as well as persistence of both putative ecotypes within this region. This Fe-titration approach, combined with transcriptomics, highlights the short-term responses of the in situ phytoplankton community to Fe-availability that are often overlooked by examining genomic content or bulk physiological responses alone. These findings expand our knowledge about how phytoplankton in HNLC Southern Ocean waters adapt and respond to changing Fe supply.

Biochemical assessment of the neurotoxicity of gold nanoparticles functionalized with colorectal cancer-targeting peptides in a rat model.

The application of gold nanoparticle-peptide conjugates as theranostic agents for colorectal cancer shows much promise. This study aimed at determining the neurotoxic impact of 14 nm gold nanoparticles (AuNPs) functionalized with colorectal cancer-targeting peptides (namely p.C, p.L or p.14) in a rat model. Brain tissue samples, obtained from Wistar rats that received a single injection of citrate-capped AuNPs, polyethylene glycol-coated (PEG) AuNPs, p.C-PEG-AuNPs, p.L-PEG-AuNPs or p.14-PEG-AuNPs, and sacrificed after 2- and 12-weeks, respectively, were analysed. Inflammation marker (tumour necrosis factor-α, interleukin-6, interleukin-1ß), oxidative stress (superoxide dismutase, catalase, glutathione peroxidase) and apoptotic biomarker (cytochrome c, caspase-3) levels were measured. Gold nanoparticle-treated groups sacrificed after 2-weeks did not exhibit any significant inflammatory, oxidative stress or apoptotic effects in brain tissue compared to the untreated control group. In brain tissue from rats that were exposed to citrate-capped AuNPs for 12-weeks, tumour necrosis factor-α and interleukin-6 levels were significantly increased compared to the untreated control. Exposure to PEG-AuNP, p.C-PEG-AuNP, p.L-PEG-AuNP and p.14-PEG-AuNP did not elicit significant toxic effects compared to the control after 12-weeks, as evidenced by the absence of inflammatory, oxidative stress and apoptotic effects in brain tissue. We thus report on the safety of PEG-coated AuNP-peptide conjugates for potential application in the diagnosis of colorectal cancer; however, exposure to citrate-capped AuNPs could induce delayed neuro-inflammation, and as such, warrants further investigation.

Management of long ureteral stenosis: Alternatives to indwelling ureteral stents.

OBJECTIF: Evaluate kidney autotransplantation (KAT) and ileal ureter substitution (IUS) practice and outcome as alternatives to indwelling ureteral stents for the management of long ureteral stenosis (US). MATERIAL: We included all patients treated for US with KAT or IUS in 5 French university urology centers between 2010 and 2018. We excluded US due to urothelial carcinoma. Primary endpoint was the preservation of ipsilateral kidney and renal function without any urinary diversion. RESULTS: 22 patients were treated with KAT (n=8, 36.4%) and IUS (n=14, 63.6%). Mean US length was 4.6cm and 6cm (P=0.52) in KAT and IUS groups respectively. US etiologies were lithiasis, iatrogenic, retroperitoneal fibrosis or extrinsic compression. US level was varied. The surgery was described as difficult because of peritoneal adhesions or major peri-ureteral fibrosis. Mean operating time and hospital stay were 336 and 346minutes (P=0.87) and 8 and 15 days respectively (P=0.001). Postoperative complications were mostly Clavien ≤2 (n=17, 77.3%). Revision surgery was required in the KAT group in 3 cases (37.5%), for textiles, renal vein thrombosis and anastomotic leak, none in the IUS group. The mean follow-up was 15.7 months. All but one (in the KAT group) ipsilateral kidneys were preserved, without renal function impairment (Δcreat +2.1 vs. +2.4µmol/l respectively, P=0.67), nor urinary diversion. CONCLUSION: KAT and IUS are safe alternatives whose indication depends on surgeons expertise. Our study pointed out the scarcity of this practice suggesting the need to refer patients to expert centers. LEVEL OF EVIDENCE: 3.

Feasibility and acceptability of conducting HIV vaccine trials in adolescents in South Africa: Going beyond willingness to participate towards implementation.

BACKGROUND: HIV/AIDS remains a leading cause of death in adolescents (aged 15 - 25 years), and in sub-Saharan Africa HIV-related deaths continue to rise in this age group despite a decline in both adult and paediatric populations. This is attributable in part to high adolescent infection rates and supports the urgent need for more efficacious prevention strategies. In particular, an even partially effective HIV vaccine, given prior to sexual debut, is predicted to significantly curb adolescent infection rates. While adolescents have indicated willingness to participate in HIV vaccine trials, there are concerns around safety, uptake, adherence, and ethical and logistic issues. OBJECTIVES: To initiate a national, multisite project with the aim of identifying obstacles to conducting adolescent HIV vaccine trials in South Africa (SA). METHOD: A simulated HIV vaccine trial was conducted in adolescents aged 12 - 17 years across five SA research sites, using the already licensed Merck human papillomavirus vaccine Gardasil as a proxy for an HIV vaccine. Adolescents were recruited at community venues and, following a vaccine discussion group, invited to participate in the trial. Consent for trial enrolment was obtained from a parent or legal guardian, and participants aged 16 - 17 years were eligible only if sexually active. Typical vaccine trial procedures were applied during the five study visits, including the administration of vaccination injections at study visits 2, 3 and 4. RESULTS: The median age of participants was 14 years (interquartile range 13 - 15), with 81% between the ages of 12 and 15 years at enrolment. Overall, 98% of screened participants opted to receive the vaccine, 588 participants enrolled, and 524 (89%) attended the final visit. CONCLUSIONS: This trial showed that adolescents can be recruited, enrolled and retained in clinical prevention trials with parental support. While promising, these results were tempered by the coupling of sexual-risk eligibility criteria and the requirement for parental/guardian consent, which was probably a barrier to the enrolment of high-risk older adolescents. Further debate around appropriate consent approaches for such adolescents in HIV prevention studies is required.

Minor changes in the macrocyclic ligands but major consequences on the efficiency of gold nanoparticles designed for radiosensitization.

Many studies have been devoted to adapting the design of gold nanoparticles to efficiently exploit their promising capability to enhance the effects of radiotherapy. In particular, the addition of magnetic resonance imaging modality constitutes an attractive strategy for enhancing the selectivity of radiotherapy since it allows the determination of the most suited delay between the injection of nanoparticles and irradiation. This requires the functionalization of the gold core by an organic shell composed of thiolated gadolinium chelates. The risk of nephrogenic systemic fibrosis induced by the release of gadolinium ions should encourage the use of macrocyclic chelators which form highly stable and inert complexes with gadolinium ions. In this context, three types of gold nanoparticles (Au@DTDOTA, Au@TADOTA and Au@TADOTAGA) combining MRI, nuclear imaging and radiosensitization have been developed with different macrocyclic ligands anchored onto the gold cores. Despite similarities in size and organic shell composition, the distribution of gadolinium chelate-coated gold nanoparticles (Au@TADOTA-Gd and Au@TADOTAGA-Gd) in the tumor zone is clearly different. As a result, the intravenous injection of Au@TADOTAGA-Gd prior to the irradiation of 9L gliosarcoma bearing rats leads to the highest increase in lifespan whereas the radiophysical effects of Au@TADOTAGA-Gd and Au@TADOTA-Gd are very similar.

The use of theranostic gadolinium-based nanoprobes to improve radiotherapy efficacy.

A new efficient type of gadolinium-based theranostic agent (AGuIX®) has recently been developed for MRI-guided radiotherapy (RT). These new particles consist of a polysiloxane network surrounded by a number of gadolinium chelates, usually 10. Owing to their small size (<5 nm), AGuIX typically exhibit biodistributions that are almost ideal for diagnostic and therapeutic purposes. For example, although a significant proportion of these particles accumulate in tumours, the remainder is rapidly eliminated by the renal route. In addition, in the absence of irradiation, the nanoparticles are well tolerated even at very high dose (10 times more than the dose used for mouse treatment). AGuIX particles have been proven to act as efficient radiosensitizers in a large variety of experimental in vitro scenarios, including different radioresistant cell lines, irradiation energies and radiation sources (sensitizing enhancement ratio ranging from 1.1 to 2.5). Pre-clinical studies have also demonstrated the impact of these particles on different heterotopic and orthotopic tumours, with both intratumoural or intravenous injection routes. A significant therapeutical effect has been observed in all contexts. Furthermore, MRI monitoring was proven to efficiently aid in determining a RT protocol and assessing tumour evolution following treatment. The usual theoretical models, based on energy attenuation and macroscopic dose enhancement, cannot account for all the results that have been obtained. Only theoretical models, which take into account the Auger electron cascades that occur between the different atoms constituting the particle and the related high radical concentrations in the vicinity of the particle, provide an explanation for the complex cell damage and death observed.

Structure and function of CrACA1, the major PM-type Ca2+-ATPase, expressed at the peak of the gravity-directed trans-cell calcium current in spores of the fern Ceratopteris richardii.

Spores of the fern Ceratopteris richardii have proven to be a valuable single-cell system for studying gravity responses. The earliest cellular change directed by gravity in these cells is a trans-cell calcium current, which peaks near 10 h after the spores are induced to germinate. This current is needed for gravity-directed axis alignment, and its peak is coincident with the time period when gravity polarises the direction of subsequent nuclear migration and rhizoid growth. Transcriptomic analysis of genes expressed at the 10-h time point revealed several that encode proteins likely to be key components that either drive the current or regulate it. Notable among these is a plasma membrane (PM)-type Ca(2+) ATPase, CrACA1, whose activity pumping Ca(2+) out of cells is regulated by gravity. This report provides an initial characterisation of the structure and expression of this protein, and demonstrates its heterologous function complementing the K616 mutant of yeast, which is deficient in PM-type Ca(2+) pump activity. Gravity-induced changes in the trans-cell Ca(2+) current occur within seconds, a result consistent with the hypothesis that the force of gravity can rapidly alter the post-translational state of the channels and pumps that drive this current across spore cells. This report identifies a transporter likely to be a key driver of the current, CrACA1, and characterises the role of this protein in early germination and gravity-driven polarity fixation through analysis of expression levels, functional complementation and pharmacological treatments. These data, along with newly available transcriptomic data obtained at the 10-h time point, indicate that CrACA1 is present, functional and likely a major contributing component of the trans-cell Ca(2+) efflux. CrACA1 is not necessary for polar axis alignment, but pharmacological perturbations of it disrupt rhizoid development. These data support and help refine the post-translational modification model for gravity responses.

[Infectious thoracic aortic aneurysms: 7 cases and literature review]. / Anévrismes infectieux de l'aorte thoracique : présentation de 7 cas et revue de la littérature.

PURPOSE: Infectious aortic aneurysms are rare conditions, being responsible of 2% of aortic aneurysms. Most published results are surgical case series concerning infected abdominal aorta. In this retrospective study, we assessed clinical features and outcome of patients presenting infectious thoracic aortic aneurysms. PATIENTS AND METHODS: Diagnosis was based upon a combination of imaging evidence for thoracic aorta aneurysm and evidence for an infective aetiology including a culture of a causative pathogen, or a favourable outcome with anti-infective therapy. Retrospective case series. RESULTS: Six men and one woman were included, with a mean age of 66 years. All the patient presented at least one cardiovascular risk factor or atherosclerosis localisation. Fever (71%) and chest pain (42%) were the most common clinical presenting manifestations. The causative pathogens were: Staphylococcus aureus (N=1), Salmonella enteritidis (N=3) and Candida albicans (N=1). The contrast-enhanced computed-tomography disclosed an aneurysm whose diameter reached more than 50 mm (N=5), that increased rapidly in size (N=5), or presented an inflammatory aspect of the aortic wall (N=4). Management was both medical and interventional: surgery (N=3) or endoluminal repair (N=4). Outcome was favourable in six patients; one patient died from aneurysm-related complications. CONCLUSION: Clinical manifestations revealing an infectious thoracic aneurysm are variable. Diagnosis should be considered in patients presenting a rapidly-growing aneurysm, especially in the presence of elevated acute phase reactants. Endoluminal repair constitutes a treatment option. The role of FDG-PET for diagnosis and follow-up remains to be defined.

The natural history of clinical operational tolerance after kidney transplantation through twenty-seven cases.

We report here on a European cohort of 27 kidney transplant recipients displaying operational tolerance, compared to two cohorts of matched kidney transplant recipients under immunosuppression and patients who stopped immunosuppressive drugs and presented with rejection. We report that a lower proportion of operationally tolerant patients received induction therapy (52% without induction therapy vs. 78.3%[p = 0.0455] and 96.7%[p = 0.0001], respectively), a difference likely due to the higher proportion (18.5%) of HLA matched recipients in the tolerant cohort. These patients were also significantly older at the time of transplantation (p = 0.0211) and immunosuppression withdrawal (p = 0.0002) than recipients who rejected their graft after weaning. Finally, these patients were at lower risk of infectious disease. Among the 27 patients defined as operationally tolerant at the time of inclusion, 19 still display stable graft function (mean 9 ± 4 years after transplantation) whereas 30% presented slow deterioration of graft function. Six of these patients tested positive for pre-graft anti-HLA antibodies. Biopsy histology studies revealed an active immunologically driven mechanism for half of them, associated with DSA in the absence of C4d. This study suggests that operational tolerance can persist as a robust phenomenon, although eventual graft loss does occur in some patients, particularly in the setting of donor-specific alloantibody.

Immunohistochemistry to identify EGFR mutations or ALK rearrangements in patients with lung adenocarcinoma.

BACKGROUND: Immunohistochemistry has been proposed as a specific and sensitive method to identify EGFR mutations or ALK rearrangements in lung tumours. PATIENTS AND METHODS: We assessed EGFR and KRAS by direct sequencing in 154 patients with lung adenocarcinoma. ALK rearrangements were assayed by FISH and RT-PCR. Immunohistochemistry was carried out and evaluated closely following published methods using recommended monoclonal rabbit or mouse antibodies. RESULTS: Thirteen of 36 exon 19 EGFR-mutated tumours (36%)-including 12 of 22 with p.Glu746_Ala750del (55%)-were positive with the 6B6 antibody that was raised against p.Glu746_Ala750del. One hundred eleven of 114 EGFR exon 19 wild-type tumours (97%) were negative with 6B6. Four of 21 exon 21 EGFR-mutated tumours (19%)-including 4 of 17 with p.Leu858Arg (24%)-were positive with the 43B2 antibody that was raised against p.Leu858Arg. One hundred twenty-two of 124 (98%) EGFR exon 21 wild-type tumours were negative with 43B2. Two of four ALK rearrangements-including two of three with ELM4-ALK fusion transcripts-were identified with the 5A4 antibody. Eleven of 13 tumours without ALK rearrangement (85%) were negative with 5A4. CONCLUSIONS: Immunohistochemistry is a specific means for identification of EGFR mutations and ALK rearrangements. It suffers, however, from poor sensitivity.

In vitro radiosensitizing effects of ultrasmall gadolinium based particles on tumour cells.

Since radiotherapy is widely used in cancer treatment, it is essential to develop strategies which lower the irradiation burden while increasing efficacy and become efficient even in radio resistant tumors. Our new strategy is relying on the development of solid hybrid nanoparticles based on rare-earth such as gadolinium. In this paper, we then evidenced that gadolinium-based particles can be designed to enter efficiently into the human glioblastoma cell line U87 in quantities that can be tuned by modifying the incubation conditions. These sub-5 nm particles consist in a core of gadolinium oxide, a shell of polysiloxane and are functionalized by diethylenetriaminepentaacetic acid (DTPA). Although photoelectric effect is maximal in the [10-100 keV] range, such particles were found to possess efficient in-vitro radiosensitizing properties at an energy of 660 keV by using the "single-cell gel electrophoresis comet assay," an assay that measures the number of DNA damage that occurs during irradiation. Even more interesting, the particles have been evidenced by MTT assays to be also efficient radiosensitizers at an energy of 6 MeV for doses comprised between 2 and 8 Gy. The properties of the gadolinium-based particles give promising opening to a particle-assisted radio-therapy by using irradiation systems already installed in the majority of hospitals.

[Mesenchymal stromal cells: Biological properties and clinical prospects]. / Cellules stromales mésenchymateuses : propriétés biologiques et perspectives thérapeutiques.

Mesenchymal stromal cells are defined as non-hematopoietic progenitors characterised by their adherence to plastic in culture, their expression of non-specific markers and their differentiation potential into cells of mesodermic lineage. Resident in numerous tissues, mesenchymal stromal cells are now available from several sources, including both adult and foetal tissues. After their administration, mesenchymal stromal cells preferentially migrate to injured tissues. Mesenchymal stromal cells have therapeutic effects in numerous animal models of tissue injury by a mechanism not yet clearly understood. Mechanisms likely involved in repair can be the production of paracrine, anti-inflammatory and anti-apoptotic factors, as well as cell replacement by their differentiation potential. Mesenchymal stromal cells possess immunosuppressive properties on both innate and adaptative immunity in vitro and in animal models of autoimmunity. Currently their immunosuppressive properties allow testing of mesenchymal stromal cells in allogenic context, although this use requires further investigations. Mesenchymal stromal cells can be isolated and expanded in vitro in clinical grade conditions. They represent a promising candidate for the cellular therapy of diseases, such as acute myocardial infarction, diabetes, graft versus host disease or neurodegenerative diseases. Critical points including the standardization of production and long term toxicity have to be resolved before their large scale use in clinical conditions.

The hexosamine biosynthetic pathway can mediate myocardial apoptosis in a rat model of diet-induced insulin resistance.

AIMS: Type 2 diabetes is characterized by deranged metabolic pathways that may result in cardiovascular complications. For example, hyperglycaemia promotes flux through the hexosamine biosynthetic pathway (HBP) leading to greater O-GlcNAcylation of target proteins, with pathophysiological outcomes. This study investigated mechanisms whereby increased HBP flux elicits myocardial apoptosis in a rat model of diet-induced hyperglycaemia/insulin resistance. METHODS: Four-week-old male Wistar rats were fed a high-fat diet (86 days) after which insulin resistance was assessed vs. matched controls. Oxidative stress was evaluated, and apoptotic peptide levels, BAD phosphorylation and overall O-GlcNAcylation assessed by immunoblotting. Protein-specific O-GlcNAcylation and BAD-Bcl-2 dimerization were determined by immunoprecipitation and Western blotting. RESULTS: Rats consuming the high-fat diet exhibited a moderate elevation in body weight, higher fasting insulin and glucose levels, and insulin resistance vs. controls. Overall protein O-GlcNAcylation was increased in hyperglycaemic/insulin-resistant hearts. In parallel, myocardial peptide levels of apoptotic markers (caspase-3, cytochrome-c, BAD) were significantly higher with insulin resistance. To gain mechanistic insight into our findings, we evaluated O-GlcNAcylation of BAD, a pro-apoptotic Bcl-2 homolog. Here we found increased BAD O-GlcNAcylation and decreased BAD phosphorylation (Ser136) in hyperglycaemic/insulin-resistant rat hearts. These data are in agreement with competition by phosphorylation and O-GlcNAcylation for the same or neighbouring site(s) on target proteins. Moreover, we observed increased BAD-Bcl-2 dimerization in hyperglycaemic/insulin-resistant hearts. CONCLUSION: The main finding of this study is that increased apoptosis in hyperglycaemic/insulin-resistant hearts can also be mediated through HBP-induced BAD O-GlcNAcylation and greater formation of BAD-Bcl-2 dimers (pro-apoptotic).

Biomarkers for the diagnosis of the stable kidney transplant and chronic transplant injury using the ProtoArray® technology.

Transplant glomerulopathy (TG), a form of chronic renal transplant rejection, carries a poor prognosis. It must be differentiated from the entity defined by the Banff '05 classification, interstitial fibrosis/tubular atrophy (IF/TA). Sequential transplant biopsies have shown that these lesions are subclinical long before clinical manifestations. The availability of biomarkers may provide an earlier diagnosis and subsequent treatment. The aim of our study was to identify serum biomarkers in kidney recipients showing TG compared with IF/TA or stable patients, using protein microarray technology. This technology detects auto- or alloantibodies in patient sera. With a high degree of statistical significance, we identified 18 antibody reactivities specific for TG; 11 for IF/TA; and 10 among stable patients. Target proteins were involved in signal transduction, transcription regulation, DNA replication and repair, cell cycle, endocytosis, cell redox, as well as glycolysis. Some markers, such as podocan and collagen XXIII among TG and tubular cell ion channels among IF/TA, possibly provide insights into the pathogenesis of the lesions.

Human recombinant anti-thyroperoxidase autoantibodies: in vitro cytotoxic activity on papillary thyroid cancer expressing TPO.

BACKGROUND: Thyroid cancers are difficult to treat due to their limited responsiveness to chemo- and radiotherapy. There is thus a great interest in and a need for alternative therapeutic approaches. RESULTS: We studied the cytotoxic activity of anti-thyroperoxidase autoantibodies (anti-TPO aAbs, expressed in baculovirus/insect cell (B4) and CHO cells (B4') or purified from patients' sera) against a papillary thyroid cancer (NPA) cell line. Anti-TPO aAbs from patients' sera led to a partial destruction of NPA cell line by complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC) and exhibited an anti-proliferative activity. Comparison of the cytotoxic activity of anti-TPO aAbs shows that B4' induced an anti-proliferative effect and a better ADCC than B4, but a lower one than anti-TPO aAbs from patients' sera. Antibody-dependent cell-mediated cytotoxicity was increased when human peripheral blood mononuclear cells were used as effector cells, suggesting that FcgammaRs, CD64, CD32 and CD16 are involved. Indeed, anti-TPO aAbs from patients' sera, but not B4 and B4', exhibited CDC activity. CONCLUSIONS: These data indicate that anti-TPO aAbs display moderate ADCC and anti-proliferative activities on NPA cells; IgG glycosylation appears to be important for cytotoxic activity and ADCC efficiency depends on FcgammaR-bearing cells. Finally, recombinant human anti-TPO aAbs cannot yet be considered as an optimal tool for the development of a novel therapeutic approach for thyroid cancer.

Quality of life and dyspnoea in patients treated with bosentan for idiopathic pulmonary fibrosis (BUILD-1).

No therapy is known to improve health-related quality of life (HRQoL) or dyspnoea in patients with idiopathic pulmonary fibrosis. The present study investigated longitudinal changes in HRQoL and dyspnoea and explored the effects of bosentan on these end-points during the Bosentan Use in Interstitial Lung Disease (BUILD)-1 trial. In total, 154 subjects received oral bosentan (n = 71) or placebo (n = 83). Changes in HRQoL and dyspnoea from baseline to month (M) 6 and up to M12 were measured using the St George's Respiratory Questionnaire (SGRQ), 36-item short-form health survey (SF-36), Transition Dyspnoea Index and Borg dyspnoea index. Overall, minimal changes occurred in measures of HRQoL and dyspnoea among placebo-treated subjects during the study. The effects of bosentan treatment on HRQoL and dyspnoea in the all-treated population were minimal. However, in the subset of subjects who had undergone surgical lung biopsy for diagnosis of idiopathic pulmonary fibrosis, treatment effects were observed up to M12 in the impact domain of the SGRQ and the physical functioning, general health and role emotional domains of the SF-36. HRQoL and dyspnoea changed minimally during the course of the present study. Observations from exploratory analyses suggested benefits of bosentan on HRQoL among patients who had undergone surgical lung biopsy for diagnosis, and they merit further investigation.

Multi-luminescent hybrid gadolinium oxide nanoparticles as potential cell labeling.

This manuscript analyses the use of newly developed hybrid gadolinium oxide nanoparticles as cell-labeling tracers. The nanoparticles are core-shell particles composed of a core of gadolinium oxide of [2-4] nm and a protecting shell of polysiloxane [1-3 nm] where different organic dyes (fluoresceine isothiocyanate (FITC) or rhodamine B isothiocyanate (RBITC)) are embedded. They are functionalized with poly(ethylene glycol)bis(carboxymethyl) to ensure their colloidal stability in biological buffers. These particles are potential multi-labeling tracers (magnetic and optical). In this paper, we show by optical imaging that they can be efficiently internalized in cells without cell alteration. The in-vitro uptake of the nanoparticles was followed in two cell lines (human fibroblasts and a human adenocarnima cell lines MCF7 cells). Nanoparticles distribution within cells was analysed by confocal analysis, and gadolinium concentration within cells was quantified by mass spectrometry (ICP-MS analysis). Nanoparticles uptake is found to be fast and efficient for both cell lines, with fluorescent labeling visible after 10 min of incubation whatever the nature of the fluorophore. The fluorescent intensity is mainly found as concentrated dots in the perinuclear region of the cells and decreases with the number of days in culture, but is still easily detectable after 3 days in culture. No significant effect on cell growth was detected. Finally, we show in this study the protective effect of the polysiloxane layer: encapsulation of RBITC within the polysiloxane shell, leads to a better photostability of this low cost dye than Cy3 and even reach a level comparable to Alexa 595. With their high photostability and long-lasting contrast properties, these hybrid luminescent nanoparticles appears thus as a versatile solution to assess multiple cell fate both in in-vitro cell model as well as in-vivo.

Cell responses to bone morphogenetic proteins and peptides derived from them: biomedical applications and limitations.

The bone morphogenetic proteins (BMPs) are cytokines of the transforming growth factor beta family. Some BMPs such as BMP-2 and BMP-7 play a major role in the development of the skeleton and the maintenance of homeostasis during bone remodelling. To date, only BMP-2 and BMP-7 have been approved by the Food and Drug Administration for specific orthopaedic applications. However, due to BMP cost, peptides derived from their knuckle epitope with osteogenic properties have been developed. BMPs are involved in many other biological events, including embryogenesis, angiogenesis and cancer. BMPs therefore have great biomedical potential as osteogenic factors and as anti-cancer agents. This review focuses on the use of BMPs and their derived peptides in biomedical delivery systems and gene therapy.

Formulation and characterization of polyphenol-loaded lipid nanocapsules.

The purpose of this study was to design and characterize two flavonoid-loaded lipid nanocapsules (LNC) by applying the phase inversion process, and to enhance their apparent solubility and/or the stability. The flavonoid-loaded LNC were characterized by particle size, encapsulation efficiency, drug leakage rates, stability and spectroscopic studies. It was observed that quercetin-loaded LNC30 (3%) and LNC60 (2%) carried a particle size of 30.3 and 55.1 nm, respectively and significant higher entrapment efficiency. Encapsulation of quercetin (QC) in LNC enabled us to increase its apparent aqueous solubility by a factor of 100. And in view of calculations and results, it seems most probable that QC is arranged at this LNC interface between the oil phase and the hydrophilic polyethylene glycol moieties of the surfactant. In addition, colloidal suspensions proved to be stable in term of encapsulation for at least 10 weeks and QC was not oxidised. With simple chemical modification of (-)-epigallocatechin-3-gallate or (-)-EGCG, it was possible to reach very high encapsulation rates (95%). Thus we obtained stable colloidal suspensions of (-)-EGCG in water over 4 weeks while free (-)-EGCG solubilised in water exhibited 100% degradation within 4h. The initial problems (solubility and stability) of these flavonoids were resolved thanks to drug-loaded LNC.